1. Field of the Invention
The present invention relates to a circuit protection apparatus for detecting whether a peripheral component is plugged, damaged, or short-circuited; in particular, to a circuit protection apparatus which is able to automatically turn on or enter into a power saving mode, and is able to totally isolate the output power and the load automatically.
2. Description of Related Art
Because of the lightening and thinning of electronic devices, users are used to be accompanied with the electronic devices. The common electronic devices, such as mobile phones, personal digital assistances (PDA), notebook computers, tablet computers, digital cameras, and digital camcorders, etc., are widely used by people, and become an indispensable part in the modern information life.
FIG. 1a shows a circuit block diagram of a short-circuit protection circuit used in universal serial bus (USB) port according to the conventional techniques. Generally, an output short-circuit protection is mainly based on the short-circuit protection by increasing or lowering the voltage within the integrated circuit (IC), and in the short-circuit protection of this kind of IC the time length of the short-circuit protection is usually set by connecting externally a RC circuit including resistors and capacitors. For example, when a short-circuit occurs, the time length when the power switch 103 stops outputting voltages and currents lies between a few tens of microseconds to a few seconds. When the time at which the power switch 103 stops outputting both the voltages and currents is reached, the power converter 102 then will continuously output voltages and currents. If the short-circuit still exists, the short-circuit protection mentioned above is then executed again. Therefore, the output is opened and then closed for several times before the short-circuit problem is solved. This is due to the fact that the objective of the short-circuit protection of this kind of IC is for protecting the IC itself, and serves as the last protection stage when other external functions for protecting the circuits are inactivated. In other words, the short-circuit protection of this kind of IC cannot work when the product is short-circuited. Unfortunately, many electronic products are designed in this manner, which makes the safety of the short-circuit protection be seriously not enough, and is very easy to damage the external instruments or the inner circuits.
In addition, this kind of IC does not have a current limitation protection, that is, when the external device generates abnormally large current because of current spike, aging, or interferences and the current is not large enough to cause a short circuit, it is still be deemed that the large current is normal and continuously outputted in this kind of IC, this situation is very easy to cause damages to the external devices.
Moreover, there are also many electronic devices, in which the circuits have no designs of short-circuit or current limitation protections, and they usually rely on the protection IC used in batteries to serve as the last protection stage of the products. However, this kind of IC still has a small chances to operate wrongly or even not operate, that is, the short-circuit protection has a small chance to be inactivated. In addition, these kinds of designs are also easy to cause damages to the electronic circuits and the load instruments. The mentioned circuits do not have the capability of detecting whether the external short-circuit or over-current situation is totally eliminated or not, and also cannot warn the users for immediately solving the situation when the short-circuit or over-current occurs. Therefore, this disclosure provides practical solutions for solving the aforementioned problems.
In addition, the modern 3C mobile products, such as a mobile power (or called as a power bank), a charger, or a voltage transformer etc., emphasize strongly the functionalities of intelligence and power saving, some products with powerful functions may include the functionalities of automatically turn-on or turn-off. FIG. 1b shows a circuit block diagram of a current limiting protection circuit of a USB port according to the conventional techniques. Please refer to FIG. 1b, the circuit includes a USB port 104, an amplifier 105, a controller 106, and a power converter 107. When the USB port 104 is connected with the peripheral component, the amplifier 105 outputs an enable signal EN. When the controller 106 receives the enable signal EN, the controller 106 leaves the power saving mode, which makes the power converter 107 to output fully electric energies. However, such detection and enabling circuits are usually accompanied with a few power consumption, for example, even out of work, the amplifier 105 still has a basic power consumption. Those power consumptions usually may influence the usage time of the battery, and is easy to generate wrong operations.